1. Field of the Invention:
The present invention relates, in general, to electrical watthour meters and, specifically, to watthour meter mounting enclosures or socket adapters.
2. Description of the Art
Electrical power is supplied to an individual site or service by external electrical power line conductors located above or below ground. In a conventional arrangement, electrical power line conductors are connected to terminals in a watthour meter socket mounted on a building wall. Electrical load conductors are connected to another set of terminals in the meter socket and extend to the electrical distribution network in the building. A watthour meter is connected to both pairs of terminals in the meter socket to measure the electric power drawn through the load conductors.
Due to the current trend toward the use of plug-in watthour meters, A to S type socket adapters have been devised which convert A-base type bottom connected watthour meter sockets to receive plug-in watthour meters. Another type of socket adapter has been devised which allows the installation of other devices between the watthour meter socket and a plug-in watthour meter.
Such socket adapters employ a generally annular base having a shell joined thereto and extending outward from one side of the base. Jaw contacts are mounted in the shell and base. Each jaw contact has a female jaw portion disposed interiorly within the shell and a male blade terminal connected to the female jaw portion and extending outward through the base for plug-in connection to the terminals in the meter socket housing.
In previous watthour meter socket adapters, the jaw contacts were of two different constructions. In one construction, the jaw contacts have a folded over design formed of a base wall fixedly mounted by a fastener to the shell of the socket adapter and two spaced sidewalls extending therefrom. The outer ends of the sidewalls are folded over inwardly between the sidewalls and terminate in parallel end flanges which slidably receive a blade terminal of a watthour meter. A blade terminal is usually fixedly connected to the base wall of the jaw contact for connection to jaw contact in a meter socket.
In the second construction, the jaw contacts are formed of a generally planar terminal having opposed first and second ends. An angularly bent spring clip is riveted at one end to an intermediate portion of the terminal and extends to a contact edge disposed in separable engagement with the first end of the terminal to form a jaw for receiving the blade terminal of a watthour meter. The spring clip forcibly biases the watthour meter terminal into secure electrical engagement with the terminal. The second end of the blade terminal extends exteriorly from the base of the watthour meter socket adapter for releasable engagement in a socket jaw contact. A cotter pin is inserted through an intermediate aperture in the terminal to fixedly mount the terminal and jaw contact in position in the watthour meter socket adapter.
In certain applications, such as automatic metering, surge suppression, etc., it is necessary to mount one or more circuit boards in the socket adapter housing. Such circuit boards must be mounted in a manner so as not to interfere with the slide-in connection of the meter blade terminals with the jaw contacts in the socket adapter. In order to mount such circuit boards in prior socket adapters, modifications to the socket adapter housing were typically necessary.
U.S. Pat. Nos. 5,023,747 and 5,572,396 disclose circuit boards mounted in close proximity to or directly on the base wall of a watthour meter socket adapter. The circuit boards have planar electrically conductive extensions with a slot therein which overlays an aperture in the base wall and receives a blade terminal or contact in a watthour meter socket adapter to electrically connect the contact and the electrical elements carried on the circuit board. While the circuit boards shown in these patents do not necessarily require modification to the socket adapter housing, the planar extensions which receive the jaw contact therethrough consume a considerable amount of space within the socket adapter housing. This poses a problem due to the limited amount of available space within a conventional socket adapter housing and limits the overall size and, therefore, the amount of circuitry that can be mounted on a circuit board.
Thus, it would be desirable to provide a watthour meter socket adapter which includes means for conveniently mounting one or more circuit boards in the housing in a non-interfering position with respect to the jaw blades of the socket adapter. It would also be desirable to provide a watthour meter socket adapter which includes means for mounting one or more circuit boards in the socket adapter housing in engagement with a safety shield mounted in the socket adapter housing. It would also be desirable to provide a watthour meter socket adapter which includes a number of separate circuit board supports which may be employed to mount one or more circuit boards in a number of different positions within the socket adapter housing. It would also be desirable to provide a unique circuit board for use in a watthour meter socket adapter which is capable of receiving an external blade terminal. It would also be desirable to provide a circuit board construction for use in a watthour meter socket adapter which enables the circuit board to automatically and, specifically, the circuit or components on the circuit board make an electrical connection to one of the contacts mounted within the socket adapter.
The present invention is a watthour meter socket adapter having unique means for mounting one or more circuit boards in a non-interfering position with respect to the jaw blades or contacts of the socket adapter.
According to the present invention, a support is carried on the housing. In one aspect of the present invention the support includes, at least one pair and, preferably, a plurality of aligned pairs of slots are formed in the housing of a socket adapter, generally at the junction of the base and sidewall of the socket adapter housing. The slot pairs can extend in any angular orientation within the socket adapter housing. The aligned pairs of slots support a circuit board generally perpendicular to the base of the socket adapter housing.
In another aspect of the invention, a plurality of posts are mounted on the base of the socket adapter housing and support a circuit board in an orientation generally parallel to the base of the socket adapter housing.
In yet another aspect of the invention, certain of the slot pairs are alignable with similar slots formed in a safety shield mountable within the housing to provide additional support for a printed circuit board which is generally disposed exteriorly of the safety shield, between the outer peripheral portion of the safety shield and the adjacent sidewall of the socket adapter housing.
In yet another aspect of the present invention, the support is in the form of aligned pairs of tubular support posts carried on the base and projecting outward therefrom for receiving a circuit board in a generally perpendicular position relative to the base.
In another aspect, an end support member is disposed adjacent to each pair of support posts and includes an outer projecting lip on an inclined end to snap mount the circuit board in the housing.
In another aspect, one of the pins of each pair of pins is formed with a shorter height relative to the base wall for supporting a circuit board in conjunction with the other pin of each pair as well as the end support pin in a generally parallel orientation with respect to the base.
In another aspect, the support includes a printed circuit board having at least one and preferably two outwardly projecting legs, each leg carrying an electrically conductive terminal or pad on one or both sides. The legs project through apertures in the base of the socket adapter housing for electrical connection to an external electrical circuit.
The support, according to one aspect of the invention, provides at least one and, preferably, a pair of open notches are formed in opposed side edges of a printed circuit board which are positioned to receive the bendable tab formed on a surge ground conductor mounted in the socket adapter housing.
In yet another aspect of the invention, the support is in the formed of aligned pairs of tubular support posts carried on the base and projecting outward from the base. Each support has a sidewall discontinuity opening to a through bore extending through the support or post. The discontinuity and open end of the through bore enable the circuit board to be inserted between aligned pairs of supports in a generally perpendicular orientation with respect to the base wall of the socket adapter housing. The open end of the through bore also enables fasteners to be inserted through aligned apertures in a circuit board oriented generally parallel to the base wall of the socket adapter housing, and into the through bore in the supports for securely fixing a circuit board in a generally parallel position with respect to the base wall.
In another aspect of the present invention, a circuit board includes at least one and possibly two opposed spring contact clips which are fixedly mounted on an outer edge of the circuit board and spaced apart to receive a blade terminal, such as a blade terminal of a watthour meter therein. An electrical circuit and/or a conductive path on the circuit board is disposed in electrical communication with the contact clips.
In yet another aspect of the invention, access is provided through the socket adapter to an electrical component mounted on the circuit board. Access is provided by an aperture formed in one of the sidewall and/or base wall of the socket adapter in which an electrical control component, such as a connector, switch, etc., can be electrically connected to the electrical component internally within the socket adapter housing and controllable externally of the socket adapter or connected to external control circuits in the case of a connector. Alternately, an aperture formed in an insulated shield mounted over the electrical contacts in the socket adapter housing may support a switch or connector to again provide electrical connection between the electrical component mounted on the circuit board and an external source.
In another aspect of the present invention, a biased arm is mounted on a circuit board and is electrically connected with a circuit, component or conductive path carried on the circuit board. An outer end portion of the biased arm projects outwardly from the circuit board. The circuit board is positioned in close proximity to one of the electrical contacts, jaw contacts, blade terminals or jaw blades of a watthour meter socket adapter such that the biased arm electrically contacts the electric contact of the socket adapter to complete an electrical circuit between the circuit or component mounted on the circuit board and the electrical contact.
In another aspect of the invention, a spring mounting jaw is releasably mountable about an edge portion of a jaw blade and receives a circuit board between the jaw blade and one spring arm of the mounting jaw. A conductive terminal or pad on the circuit board engages the mounting jaw or is biased into contact with one jaw blade by the mounting jaw to complete a circuit with the jaw blade and provide electrical power from the jaw blade to the electrical components on the circuit board. In this configuration, electrical power is delivered to the circuit board without the need for mechanical fasteners or connectors usually used to supply power to circuit boards in a socket adapter housing.
In another aspect, the circuit board mounting supports described in the present invention are also adapted for receiving flanges carried or formed on electrical components, such as relays, timers, telephone modems, circuit breakers, etc. This enables such components to be releasably mountable in the housing of a socket adapter again without the need for mechanical fastening arrangements. This reduces the overall cost of manufacturing the socket adapter as well as making the socket adapter extremely versatile in receiving auxiliary components without the need for modification to the existing socket adapter housing and jaw blade structure.
In the various embodiments of the present invention, one or more circuit boards can be easily mounted in the housing of a watthour meter socket adapter housing. The circuit board supports can be positioned to support the circuit boards exteriorly of a safety shield in the space between the shield and the adjacent sidewall of the housing. Alternately, the circuit board supports may be employed without a shield and positioned at various locations around the periphery of the sidewall of the housing and/or on the base wall or on the base wall between the socket adapter jaw contacts for supporting one more circuit boards in various orientations about the jaw blades without interfering with the function of the jaw blades in releasably receiving blade terminals of a watthour meter.
The present invention also provides a unique snap-in connection of a circuit board in a socket adapter housing thereby eliminating the need for separate mechanical fasteners and manufacturing/assembling operations necessary to securely fasten the circuit board to the base wall of the socket adapter as in prior socket adapters.
The unique provision of a circuit board with outwardly projecting legs enables a circuit board to be mounted in any one or more pair of apertures typically disposed in a socket adapter. The circuit board provides a convenient location for mounting electrical components within a socket adapter, with access being provided to the electrical component through plugs or switches mounted in apertures in the sidewall or base wall of the socket adapter or in an aperture in a safety shield overlaying the jaw contacts of the socket adapter.
The provision of a resilient arm projecting from the circuit board and electrically connected to an electrical component or circuit on the circuit board enables an electrical circuit to be completed between a circuit or electrical component on the circuit board and one of the electrical contacts in the socket adapter, such as a line jaw blade or jaw contact, to provide electrical power or a ground connection to the circuit board.